Yamaha YZ450F 2021 - Changing the Coolant; Checking the Cooling System

ENGINE
3-21
tilled water is not available, soft water may
be used.
4. Start the engine, warm this up for several
minutes, and then stop it.
5. Check:
• Coolant level
TIP
Before checking the coolant level, wait a few
minutes until the coolant has settled.
EAM30211
CHECKING THE COOLING SYSTEM
1. Remove:
• Seat
• Side cover (left/right)
• Air scoop (left/right)
Refer to “GENERAL CHASSIS” on page 4-1.
• Air filter case cover
Refer to “THROTTLE BODY” on page 7-4.
2. Check:
• Radiator
• Radiator hose
Crack/damage  Replace.
Refer to “RADIATOR” on page 6-2.
3. Install:
• Air filter case cover
Refer to “THROTTLE BODY” on page 7-4.
• Air scoop (left/right)
• Seat
• Side cover (left/right)
Refer to “GENERAL CHASSIS” on page 4-1.
EAM30212
CHANGING THE COOLANT
WARNING
EWA13030
A hot radiator is under pressure. Therefore,
do not remove the radiator cap when the en-
gine is hot. Scalding hot fluid and steam may
be blown out, which could cause serious in-
jury. When the engine has cooled, open the
radiator cap as follows:
Place a thick rag or a towel over the radiator
cap and slowly turn the radiator cap counter-
clockwise toward the detent to allow any re-
sidual pressure to escape. When the hissing
sound has stopped, press down on the radi-
ator cap and turn it counterclockwise to re-
move.
1. Place a container under the engine.
2. Remove:
• Coolant drain bolt “1”
3. Remove:
• Radiator cap
Slowly loosen the radiator cap to drain cool-
ant.
TIP
When the radiator cap is loosened, coolant will
gush out transversely; therefore, bring the con-
tainer near to the outlet.
4. Thoroughly flush the cooling system with
clean tap water.
5. Install:
• Copper washer
• Coolant drain bolt
6. Pour coolant.
WARNING
EWA13040
• If coolant splashes in your eyes, thorough-
ly wash them with water and consult a doc-
tor.
• If coolant splashes on your clothes, quickly
wash it away with water and then with soap
and water.
• If coolant is swallowed, induce vomiting
and get immediate medical attention.
NOTICE
ECA13481
• Adding water instead of coolant lowers the
antifreeze content of the coolant. If water is
used instead of coolant, check, and if nec-
essary, correct the antifreeze concentra-
Coolant drain bolt
10 N·m (1.0 kgf·m, 7.4 lb·ft)
Recommended coolant
High quality ethylene glycol
anti-freeze containing anti-cor-
rosion for aluminum engine
Radiator (including all routes)
1.03 L (1.09 US qt, 0.91 Imp.qt)
Coolant mixing ratio
1:1 (Coolant:Water)
1
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